Continuous flow isotope ratio mass spectrometry of carbon dioxide trapped as strontium carbonate

Harris, David J.; Porter, L. K.; Paul, Eldor A.

doi:10.1080/00103629709369827

Cited by 97 publications

(51 citation statements)

References 9 publications

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“…Oxygen isotope analyses of sulfate followed a method similar to that of Kornexl et al (1999) with the modifications that the analyses were performed at 1300°C and that nickelized graphite was added to BaSO 4 samples as a pyrolysis aid. Carbon isotope analyses were performed after the method of Harris et al (1997). NIST standard NBS-127 BaSO 4 was used as an isotope standard for sulfate-d 18 O analyses, using the NIST-certified value of d 18 O = +9.3%.…”

Section: Stable Isotope Methodsmentioning

confidence: 99%

Geochemistry of Flooded Underground Mine Workings Influenced by Bacterial Sulfate Reduction

Roesler¹,

Gammons

Druschel

et al. 2007

Aquat Geochem

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Unlike the majority of the water in the flooded mine complex of Butte Montana, which includes the highly acidic Berkeley pit lake, groundwater in the flooded West Camp underground mine workings has a circum-neutral pH and contains at least 8 mM aqueous sulfide. This article examines the geochemistry and stable isotope composition of this unusual H 2 S-rich mine water, and also discusses problems related to the colorimetric analysis of sulfide in waters that contain FeS (aq) cluster compounds. The West Camp mine pool is maintained at a constant elevation by continuous pumping, with discharge water that contains elevated Mn (90 mM), Fe (16 mM), and As (1.3 mM) but otherwise low metal concentrations. Dissolved inorganic carbon in the mine water is in chemical and isotopic equilibrium with rhodochrosite in the mineralized veins. The mine water is under-saturated with mackinawite and amorphous FeS, but is supersaturated with Cu-and Zn-sulfides. However, voltammetry studies show that much of the dissolved sulfide and ferrous iron are present as FeS (aq) cluster molecules: as a result, the free H 2 S + HS À concentration of the West Camp water is poorly constrained. Concentrations of dissolved sulfide determined by colorimetry were lower than gravimetric assays obtained by AgNO 3 addition, implying that the FeS (aq) clusters are not completely extracted by the Methylene Blue reagent. In contrast, the clusters are quantitatively extracted as Ag 2 S after addition of AgNO 3 . Isotopic analysis of co-existing aqueous sulfide and sulfate confirms that the sulfide was produced by sulfate-reducing bacteria (SRB). The H 2 S-rich mine water is not confined to the immediate vicinity of the extraction well, but is also present in flooded mine shafts up to 3 km away, and in samples bailed from mine shafts at depths up to 300 m below static water level. This illustrates that SRB are well established throughout the southwestern portion of the extensive (>15 km 3 ) Butte flooded mine complex.

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Section: Stable Isotope Methodsmentioning

confidence: 99%

Geochemistry of Flooded Underground Mine Workings Influenced by Bacterial Sulfate Reduction

Roesler¹,

Gammons

Druschel

et al. 2007

Aquat Geochem

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“…An aliquot of each NaOH solution was analyzed for total inorganic C using a Shimadzu 5050A TOC analyzer. Another aliquot was precipitated as SrCO 3 and then analyzed for d 13 C using a PDZ Europa ANCAeGSL elemental analyzer interfaced to a PDZ Europa 20e20 isotope ratio mass spectrometer (Harris et al, 1997). The d 13 C values measured in SrCO 3 were corrected for contamination from carbonate in the NaOH stock solution and from sample handling (Cheng et al, 2003).…”

Section: Measurements and Calculationsmentioning

confidence: 99%

Rhizosphere priming effects on soil carbon and nitrogen mineralization

Zhu

Gutknecht

Herman

et al. 2014

Soil Biology and Biochemistry

339

153

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a b s t r a c tLiving roots and their rhizodeposits affect microbial activity and soil carbon (C) and nitrogen (N) mineralization. This so-called rhizosphere priming effect (RPE) has been increasingly recognized recently. However, the magnitude of the RPE and its driving mechanisms remain elusive. Here we investigated the RPE of two plant species (soybean and sunflower) grown in two soil types (a farm or a prairie soil) and sampled at two phenological stages (vegetative and mature stages) over an 88-day period in a greenhouse experiment. We measured soil C mineralization using a continuous 13 C-labeling method, and quantified gross N mineralization with a 15 N-pool dilution technique. We found that living roots significantly enhanced soil C mineralization, by 27e245%. This positive RPE on soil C mineralization did not vary between the two soils or the two phenological stages, but was significantly greater in sunflower compared to soybean. The magnitude of the RPE was positively correlated with rhizosphere respiration rate across all treatments, suggesting the variation of RPE among treatments was likely caused by variations in root activity and rhizodeposit quantity. Moreover, living roots stimulated gross N mineralization rate by 36e62% in five treatments, while they had no significant impact in the other three treatments. We also quantified soil microbial biomass and extracellular enzyme activity when plants were at the vegetative stage. Generally, living roots increased microbial biomass carbon by 0 e28%, b-glucosidase activity by 19e56%, and oxidative enzyme activity by 0e46%. These results are consistent with the positive rhizosphere effect on soil C (45e79%) and N (10e52%) mineralization measured at the same period. We also found significant positive relationships between b-glucosidase activity and soil C mineralization rates and between oxidative enzyme activity and gross N mineralization rates across treatments. These relationships provide clear evidence for the microbial activation hypothesis of RPE. Our results demonstrate that rootesoilemicrobial interactions can stimulate soil C and N mineralization through rhizosphere effects. The relationships between the RPE and rhizosphere respiration rate and soil enzyme activity can be used for explicit representations of RPE in soil organic matter models.Published by Elsevier Ltd.

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“…S3). The trapped CO 2 was precipitated as SrCO 3 and measured for 13 C (Harris et al 1997). In the second growing season, we used a Cavity Ringdown Spectrometer (G2131-i, Picarro, USA, Fig.…”

Section: Soil Co 2 Fluxesmentioning

confidence: 99%

The effects of heating, rhizosphere, and depth on root litter decomposition are mediated by soil moisture

et al. 2017

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Continuous flow isotope ratio mass spectrometry of carbon dioxide trapped as strontium carbonate

Cited by 97 publications

References 9 publications

Geochemistry of Flooded Underground Mine Workings Influenced by Bacterial Sulfate Reduction

Geochemistry of Flooded Underground Mine Workings Influenced by Bacterial Sulfate Reduction

Rhizosphere priming effects on soil carbon and nitrogen mineralization

The effects of heating, rhizosphere, and depth on root litter decomposition are mediated by soil moisture

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